1. Field of the Invention
The present invention relates to a locking structure for a clamp, and more particularly to a locking structure for a clamp which enables a component to be fixed to a counterpart member such as an automotive body panel to be securely locked and fixed through a through hole in the counterpart member.
2. Description of the Background Information
Conventionally, a clamp 1 is generally used as a member to fix elements to portions of an automotive body, as shown in FIGS. 5A and 5B. This clamp is equipped with a pair of locking wings 4 formed to extend rearwardly from the tip section of support pin 3 which projects from base plate section 2. The outer surface sections of the tips of locking wings 4 are equipped with locking stepped sections 4a to be locked through a through hole Pa formed on automotive body panel P.
To lock the clamp 1 to automotive body panel P, first, the tip of support pin 3 is inserted forcefully into through hole Pa of automotive body panel P. Then, inner periphery of through hole Pa pushes locking wings 4 partially closed against their elastic resistance. When support pin 3 is pushed deeper into through hole Pa until base plate section 2 comes in contact with a surface of automotive body panel P, locking wings 4 elastically recover to open, and then locking stepped sections 4a are locked against an opening peripheral section of through hole Pa.
In this manner, clamp 1 does not come out of through hole P and remains locked and fixed. As it is shown in FIG. 5B, however, the only sections of clamp 1 which come in contact with the inner peripheral surface of through hole P are locking stepped sections 4a and portion of support pin 3. Gaps appear between clamp 1 and through hole P. Therefore, these gaps allow foreign objects and water to flow in, and it is difficult to apply clamp 1 to locations where dust control or water proofing is necessary.
Moreover, even if through hole P is an elongated hole, there is an issue in that clamp 1 easily yields to a rotational force applied on clamp 1 and rotates. In other words, the elasticity of locking wings 4 allows locking stepped sections 4a to easily deform and locking wings 4 to close as clamp 1 rotates. Therefore, locking wings 4 can not prevent clamp 1 from rotating. When a rotational force is applied to clamp 1, there is a possibility that locking stepped sections 4a come loose. When clamp 1 rotates in this manner, a component to be fixed which is equipped with clamp 1 rotates as well. Thus, the component to be fixed does not remain at a fixed location and there is a concern in that it may interfere with other components and elements in the vicinity. Moreover, as an example, when clamp 1 is employed to temporarily fix a component, for determining a final position for the component, the component can be fixed by tightening bolts on other locations. However, there is the problem that the component may move if the clamp 1 rotates, making it difficult to fix the component.
Hence, there are clamps such as a clamp 1′ disclosed in Japanese Patent Publication No. 3,250,359, depicted in FIGS. 6A–6D, in which projecting anti-rotational ribs A and B, which are separate from locking wings 4′, are provided on a support pin 3′ of clamp 1′, so that anti-rotational ribs A and B come in contact with the inner periphery of through hole Pa, thereby preventing clamp 1′ from inadvertently rotating (Patent Citation 1).
Even the clamp 1′, however, has a construction in which portions of locking wings 4 come in contact with the inner peripheral surface of through hole Pa. Hence, when an excess rotational force is applied to clamp 1′, locking wings 4′ still deform against elastic resistance to close, thereby making it difficult to provide secure locking against rotation. Moreover, although the existence of anti-rotational ribs A and B enables clamp 1′ to have a greater number of areas to come in contact with the inner peripheral surface of though hole Pa, locking wings 4′ themselves have a structure in which they are locked on the inner peripheral surface of though hole Pa, and elastically open and close in an independent manner. Therefore, gaps can not be eliminated and it is difficult to provide for perfect protection against dust and water.